Why does the view became black?

I started UE4 through VS2013(Ctrl+F5), with command parameters “-opengl4”.
It was normal at the beginning, but a few minutes later It became black. Why?

It would be normal if not using opengl mode.
My graphics card is GTX770.

Hi xiaofeii,

What version of the engine are you using? Approximately how long do you have to wait before the black section appears, and does it happen even if you don’t do anything in the Editor?

Hi Tim Lincoln,

Thank you for your reply!
The version is 4.1.1.
5-10 seconds later it will happen.
It happens even if I don’t do anything, but It will happen sooner if I move toward closely the floor using my left mouse button.

Hi xiaofeii,

Which of the project templates are you using?

Blank template, the simplest way.

Hi xiaofeii,

I have tried periodically to reproduce this issue and have been unsuccessful. Are you still experiencing the same problem?

Hi xiaofeii,

We have not heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. If you are still experiencing the issue you reported, please respond to this message with additional information and we will offer further assistance.

Thank you.